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The calcium dependency of mucus glycoconjugate secretion by canine tracheal explants
Author(s) -
Barbieri Edward J.,
Bobyock Emil,
Chernick Warren S.,
McMichael Robert F.
Publication year - 1984
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1984.tb16459.x
Subject(s) - calcium , mucus , endocrinology , methacholine , calcium in biology , medicine , secretion , verapamil , glycoconjugate , extracellular , chemistry , biology , biochemistry , ecology , respiratory disease , lung
1 Canine tracheal explants, incubated overnight with [ 14 C]‐glucosamine, elicited an enhanced secretion of ethanol‐precipitated 14 C‐labelled glycoconjugate when challenged with methacholine, 10 μ M . 2 Explants were rendered deficient in total calcium content and unresponsive to methacholine, 10 μ M , by incubating them in calcium‐free medium for 18 to 22 h; however, the secretory response to the cholinergic agonist was restored with the addition of calcium to the medium. 3 A dose‐response relationship resulted when explants were challenged with methacholine in nutrient medium containing varied calcium concentrations (0.45 to 7.2 m M ); alterations in the calcium concentration in the absence of methacholine had no significant effect on the basal secretion of 14 C‐labelled glycoconjugate. 4 The calcium‐selective ionophore A23187, 10 μ M , stimulated [ 14 C]‐glycoconjugate secretion and induced the most significant effect in the presence of nutrient medium containing calcium. 5 Verapamil, 10 μ M , a calcium‐entry blocker failed to inhibit basal or stimulated [ 14 C]‐glycoconjugate secretion; however, the intracellular calcium antagonist TMB‐8, 10 to 100 μ M , inhibited methacholine‐induced [ 14 C]‐glycoconjugate secretion in a dose‐dependent manner. 6 These data suggest that respiratory mucus secretion is a calcium‐dependent process and that intracellular calcium is more vital than extracellular calcium in supporting this phenomenon.